Television apparatus



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W ls756a232 SUBSTiTUTE FOR MISSNG XR TELEVISION APPARATUS Filed Feb. 17,1928 t may 2 q Z5 Qg QM Q7/0470 v Patented Apr. 29, 1930 JOSEPH JOHNARNAUD, OF SOUTH MILWAUKEE, WISCONSIN TELEVISION APPARATUS Applicationfiled February 17, 1928. Serial No. 255,042

This invention relates to television apparatus. F Objects of thisinvention are to provide a television apparatus in which pictures mayshe sent by wireless means or by wire means from one station to anotherso that accomplete picture is formed in a fraction of a second, thuspermitting the sending of moving pictures by wireless means or by wiremeans from one station to another station. Further objects are toprovide a television apparatus in which reliable and simple means areemployed for causing a searching ray to travel over the entire surfaceof the object 1 or picture, and in which the receiving means is equippedwith a similar device for causing the projected my to travel over theentire screen, with means for controlling the intensity of illumination'at the receiving station in exact proportion to the light and shadow atthe sending station so that an exact reproduction occurs. v

Further objects are to provide a television apparatus having thecharacteristics noted above 'which is of very simple construction andwhich'may be relatively easily operated. An embodiment of the inventionis shown in the accompanying drawings in which:

The single figure is a diagrammatic view showing the televisionapparatus both at the sending and receiving end.

Referring to the drawing, it will be seen that a projectinglantern 1 isprovided for furnishing a single beam of light which, in reality,constitutes almost a point. or thin pencil of light. This ray of lightas it passes from the lamp is indicated by the reference character 2,and it will be seen that the ray may be intercepted at regular and rapidintervals by means of the rotating disc 3 driven in any suitable manner,as by means of the motor 4. The disc 3 is provided with a plurality ofapertures 5 through which the ray of light passes, so that the light iscut off and. turned on at regular intervals to provide sharp pulses oflight.

The ray of light is received by means of a small mirror 6 attached to atuning fork 7 which is approximately horizontal in position, The ray oflight is reflected from the mirror'6 along the path 8 and'falls upon themirror 9 carried by a vertical tuning fork 10. From this point, the rayof light passes along the path 11 upon the picture or object such,

for example, as the face of a person, as indi- 5 cated by the referencecharacter 12.

From the apparatus thus far. described, it is evident that, as thetuning forks vibrate, the fork 7 will cause the ray to travelhorizontally across the screen or object and the fork 10 will cause theray to travel yertically across the screen or object. If the forks haveperiods which bear a definite .relation to each other as 1 to 1, 1 to 2,1 to 3, etc., the well known Lissajous curves will be formed. However,this result is not desired for there would be portions of the screenwhich would not be illuminated. Instead, in this invention, the periodsof the forks are so related that the ray will pass over and illuminatesuccessively all portions of the screen.

Theoretically, this last result may be secured by making the periods offorks incommensurate so that re ular Lissajous figures will not beformed ut instead-the ray, as stated, will pass over every portion ofthe screen. Practically, if the periods are not incommensurate, but bearto each other some ratio not too simple, then the curve will bereentrant. That is, it will trace out a line so closed on itself andwill then retrace and ijetrace this same line indefinitely. All that isnecessary is that the adjacent, lines of the figure shall be 'closeenoughto blend into a continuous picture. The number j f ib 5 tions'ofthe forks per second will'determine the number of trips over the screenthat the spot of light or ray "oflight will execute per second. The mostsuitable ratio of the periods of the forks can best be obtained bytrial. Ifdesired, one or both of theaforks may be provided withrasliding weight so that the period can be 'adjusted.. g

i The light reflected from the screen or obect is condensed by means ofthe optical apparatus 13 provided with condensing-1 lens and falls upona photoelectric cell 14 whichmay be a selenium or other light sensitivecell. The cell controls an amplifier-15 which may be-of the vacuum tubetype and such amplitier in turn controls a modulator 16 and thusmodulates the high frequency energy passing to the antenna 17,-such highfrequency energy being su plied by means of the oscillator 18 in a wellown manner.

From the apparatus thus far descr1bed,1t is evident that the wirelesswaves radiating from the antenna 17 will be in exact accordance with theshadow or light effect of the object or screen at the particular pointilluminated by the travelling or searching ray, and that these wirelesswaves will vary continuously as to amplitude or ener y transmitted asthe searching ray passes rom one colored or shadowed portion to adifferent portion of the object or screen.

The receiving apparatus consists of an antenna 19 connected to areceiver 20 which amplifies the received waves and controls a neon orother li ht producing tube 21, which has a substantia ly instantaneousresponse to the electric energy supplied.

In this way the tube 21 will be illuminated more or less in exactproportion to the strength of the wireless waves received andconsequently in exact accordance with the brightness or darkness of theportion of the object or screen over which the'searching ray 11 ispassing at the sending end.

- The light from the tube 21 is picked up by the optical apparatus 22provided with condensing lenses and producing a substantiallycylindrical tiny beam of light 23. This beam of light 23 is received bya mirror 24.-

- carried by a vertical tuning fork 25. It is reflected and falls upon amirror 26 carried by the horizontal tuning fork 27. From this point, theray of light passes to the receiving screen 28. If desired, it may passthrough a plate 29 formed in a manner hereinafter described. It isevident that the vertical tuning fork 25 must have the same period ofvibration as the vertical tunin fork 10, and that the horizontal tuningfork 27 must have the same period of vibration as the horizontal tuningfork 7 Any suit.- able means may be employed for keeping the tuningforks in operation and in synchro- II nism, such for example, as theelectromagtions of the searchingray. intensity of the pro ected beam 23varies in netic actuating means commonly known.

It is to be noted that the ray of light projected upon the screen 28move in exact accordance with the searching ray 11 and will consequentlyfall upon the same portion of the screen as the searching ray at allposinasmuch as the exact accordance, with the amount of light receivedby the photoelectric cell 14, it is apparent that the ray will bealternately illuminated in exact step with the brilliancy of the lightreflected from the articular portion of the object or screen i uminatedby the searching ray at any given instant.

It is also to be noted that, inasmuch as the tuning forks have simpleharmonic motions, the'outer edge of the screen will have the light uponit for the greatest length of time. T

remained for the greatest length of time and L therefore will exactlytemper or proportion the lightin of the screen 28 so as to insure 'apicture 0 uniform density throu hout.

While the member 29 is referre to as a plate or photographic plate, itis to be understood that such expression is not intended as limiting asa film or other photographic member may be employed provided it has thecharacteristics noted above.

It is to be noted that the rotating disc 3 provides sharp pulses oflight which produces in the reproduced figure the efiect-of a half tone.In addition to this, it has been found that the light sensitive cell 14,if it has any lag whatsoever, will be more effective in reproducing theexact proportionate degree of current if it is illuminated bysharppulses of light which seem to eliminate the effect of the time lag ofthe cell. It is, of course, to be understood that the rotating disc maybe omitted in certain forms of the apparatus. The use of a neon lamp ortube 21 is desirable although other tubes may be used, because the neontube gives a substantially instantaneous response to the electriccurrent.

Further than this, it is clear also that a battery of photoelectriccells could be employed in place of the single photoelectric cellillustrated by the transmitting portion of the apparatus.

It is apparent that the tuning fork system can also be used to singleoutone spot of a constantly illuminated field. For example, the apparatusconsisting of the elements 13 to 18, could be substituted for the lightpro jecting apparatus and associated with the tuning forks and mirrorsto cause the moduconstant and the modulating or light rescreen for thepur ose of illustration, it is to be distinctly un rstood that themember While the member 12 has been'shown as a 12 may be replaced by anyobject whose picture it is desired to transmit. For example, a person orface may be substituted for the screen 12, or pictures themselves may beused.- In all cases, the'reproduced pictures will bean exactreproduction of the object over which the searching ray passes.

Other forms of light guiding means may be employed. For example, amirror may be carried by a T-shaped bar, the mirror being placed at thepoint of union of the shank or stem with the cross member of the bar,and in the plane of the T. The shank may be resilient and the transverseportion of the.

T-shaped member may be operated by means 'of' a plurality ofelectromagnets controlled in any suitable manner; for example, by

means of vacuum tubes, so as to give the mirror motion about twodistinct axes at right angles to .each other.

It is evident that the invention lends itself admirably to theconventional wireless transdetermined rule; and an equalizing screenthrough which said ray passes, said screen consisting of a photogra hicplate having its density varying in accordance with said rule.

6. In a television apparatus, the combination of: a source of light;means for projecting a ray of light from said source and moving said myin accordance with a predetermined rule; and an equalizing screenthrough which said ray passes, said screen consisting of 'a photographicplate havingdifferent degrees of density produced by dif- Wisconsin. 7

JOSEPH JOHN ARNAUD.

ated above, is extremely simple in construc- Y tion and is highlypractical.

Although the invention has been described in considerable detail, suchdescri tion is in tended as illustrative rather than 'miting as theinvention may be variously embodied and as the scope of such inventionis to be determined as claimed.

I claim:

1.. The method of preparing an equalizing screen for a searching ray,which traverses a projection screen according to a rule that obliges itto remain longer directed tosome portions of the screen than to others,or traces lines more congested in some portions of the projection screenthan in others; said method:

consisting in: causing this ray to traverse a photographicplate-according to said rule; and then developing said plate. p

2. ,The method .of making an equalizing screen fora television apparatusin which amoving ray is em loyed, said method comprislng placing a potographic plate in the path of said ray, causing said ray to traversesaid plate, and subsequently developing said p a e. Y

g 3. An equalizing screen comprising "a photographic plate havingdifi'erent degrees of density from point to point throughout its extentproduced by exposing different portions of the screen to differentdegrees.

4. An equalizing screen comprising a photographic plate having differentdegrees of exposure throughout its extent to produce difi'erent degreesof density according to a predetermined rule.

5. -In a television a paratus, the combination of: a source of ight;means for proectmg a ra of light from said source and moving sai ray inaccordance with a pre-

